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Extruder Screw Barrel Causes Of Wear

1. Each kind of plastic, has an ideal plastic processing temperature range, should control the barrel processing temperature, so that it is close to the temperature range. Granular plastic from hopper into the material cylinder, the first will reach the feeding section, in the feeding section will appear dry friction, when these plastics are not heated, melting uneven, it is easy to cause the inner wall of the cylinder and screw surface wear increased. Similarly, in the compression and homogenization segments, if the melting state of the plastic is uneven, will also cause wear and tear increase.

2. Screw in the barrel of rotation, the friction between the material and the two, so that the work of the screw and the barrel of the surface gradually wear: the diameter of the screw gradually reduced, the diameter of the inner hole of the barrel gradually increased. In this way, the screw and barrel of the matching diameter gap, with the gradual wear and tear of the two a little increase. However, because the front of the machine barrel and the resistance of the shunt board did not change, this increased the extrusion material in advance of the leakage flow, that is, the material from the diameter gap to the feed direction of the flow increased. Results the production of plastic machinery decreased. This kind of phenomenon also causes the material to stay in the barrel time to increase, causes the material decomposition. In the case of polyethylene, the decomposition of hydrogen chloride gas strengthens the corrosion of the screw and barrel.

3. Rotate speed should be adjusted properly. Some plastics are fortified with additives such as fiberglass, minerals or other fillers. The friction of these materials on metal materials is often much larger than that of molten plastic. In the injection molding of these plastics, if the high rotational speed into, while increasing the shearing force on the plastic, but also will strengthen the corresponding production of more shredded fiber, the shredded fiber containing sharp end, so that the wear strength greatly increased. The scraping action of inorganic minerals is not small when the metal surface is gliding at high speed. So the speed should not be adjusted too high.

4. Materials such as calcium carbonate and glass fiber filler materials, can speed up the screw and barrel wear.

5. Because the material is not plasticizing evenly, or has the metal foreign body mixes the material, causes the screw rotation torque force to increase suddenly, this kind of torque surpasses the screw strength limit, causes the screw to wring. This is a very bad accident.